Single-switch 3φ PWM low harmonic rectifiers

Existing 3φ AC-DC low-harmonic rectifiers are costly and require complex control schemes to minimize input current harmonics. Introduced here are two new classes of low cost 3φ AC-DC high power factor/low harmonic controlled rectifiers. These are derived from parent DC-DC converter topologies containing boost-type inputs and buck-type inputs. With a single active switch in addition to the diode bridge rectifier, the converters are capable of drawing a high-quality input current waveform naturally at nearly unity power factor. Thus, a simple 3φ AC-DC high power factor rectifier is obtained. Two algorithms are introduced in this paper for constructing a 3φ AC-DC high-quality rectifier. These algorithms depend on the simple switched-mode boost-type input converter and buck-type input converter modified by an input filter. For most known DC-DC converters which belong to these classes, there are corresponding 3φ AC-DC high power factor topologies, which use the same number of transistors and use six additional fast diodes. Analytical and simulation results are supplied to demonstrate the validity of the concept